JP2019535534A - Structured seed layer - Google Patents

Abstract

The present invention relates to a method for forming a structural seed layer for depositing carbon nanotubes (16) on a structured seed layer, wherein first a metal layer (2) coated on a substrate (1) is laser-coated. By being energized by the beam (4), the metal layer (2) is transformed into an isolated island (3), the laser beam (4) is expanded into a beam (5) that is linear in cross section, and The linear exposure area (15) of (2) is simultaneously exposed to it, and the exposure area (15) moves in a direction transverse to the direction of extension on the metal layer (2). The apparatus for carrying out the method comprises means (9, 10) for transporting a substrate (1) coated with a metal layer (2) and a laser (6) for generating a laser beam (4). Means (7) for expanding the laser beam in order to generate a linear exposure area (15), said means (7) comprising a linear exposure area (15) on the substrate (1). Is configured to extend perpendicularly to the transport direction of. [Selection diagram] Fig. 1

Description

  The present invention relates to a method of forming a structured seed layer for depositing carbon nanotubes on a structured seed layer, wherein a metal layer pre-applied on a substrate is energized by a laser beam so that the metal layer Is transformed into an isolated island.

  The invention further relates to an apparatus for carrying out the method.

  U.S. Patent No. 6,057,049 describes the manufacture of a seed cell arrangement for depositing carbon nanotubes CNTs. The metal layer deposited on the substrate is rapidly heated (rapid thermal annealing) by plasma or laser beams or other methods. Thereby, a droplet-like structure is formed that is located close to and adjacent to each other.

  U.S. Patent No. 6,057,032 describes the use of a laser beam that is linearly expanded for laser welding. In this case, a mask is used, which is placed on the workpiece.

  Patent Document 3 describes a laser including a beam deforming lens that linearly expands a laser beam. With a laser mask, this laser is used for mask welding of plastic parts.

  Non-Patent Document 1 describes a method for forming a regular droplet arrangement on a surface. On the surface, first a “nanolattice” configuration of linear grids extending in parallel is applied. Metal is applied to intersect the grid. By irradiating a single laser pulse, metal droplets of equal size are formed at the intersections of the metal lines and the grating. In contrast, when the closed layer is acted upon by a laser pulse, irregularly sized and unevenly distributed droplets are formed.

From Non-Patent Document 2, it is known to manufacture semiconductor nanowires by depositing metal islands (islands) using SiO ₂ globules on the surface on which nanotubes are formed.

US Patent Application Publication No. 2009/0121219 European Patent No. 09972619 European Patent Application Publication No. 2591875

"The fabrication of periodic metal nanodot arrays through pulsed laser melting induced fragmentation of metal nanogratings", Nanotechnology 20 (2009) 285310 (June 23, 2009) "Das Wachstum von Nanodrahten", Physik Journal 4 (2005) Nr. 5, P. 29

  The object of the present invention is to provide a means by which the formation of seed zones for CNT coating can be reproducibly controlled, in particular the size of the seed zones and their distance can be set reproducibly.

  This object is achieved by the invention described in the claims, and the dependent claims not only show advantageous improvements of the invention disclosed in the independent claims, but also show independent solutions to the problem.

First, it is proposed to generate a linear exposure area. In that case, the entire surface of the exposed area is simultaneously illuminated during continuous or pulsed exposure of the linear exposure area, unlike a point-like laser beam that moves from line to line during writing and produces only local heating. Exposed to output.
According to the present invention, the linear exposure region moves on the metal layer previously deposited on the substrate at an adjustable speed. This can be done by moving the laser beam, but preferably by moving the substrate. In that case, it is particularly preferred that the substrate is unwound from the storage roll and wound up again on the second storage roll. In this way, a thin region moves over the substrate, which simultaneously heats the metal layer at about the same temperature across its entire width corresponding to the width of the substrate, so that a temperature gradient occurs substantially only in the writing direction, It does not occur in the lateral direction with respect to the writing direction.
The diameters of the island-like seed zones and their distances can be adjusted by laser power parameters, pulse energy or pulse width and substrate transport speed as required. As further parameters for pre-setting the size and distribution of island-like seed zones on the substrate surface, the material thickness of the metal layer and the direction of the expanded laser beam corresponding to the width of the exposure area Length is used.
Preferably, the length of the linear exposure region extends over the entire substrate, so that the width of the expanded laser beam is about 20 mm to 1000 mm. The laser beam expanded into a linear cross section can have a length of 0.5 mm to 5 mm. This length corresponds to the width of the exposure area. The wavelength of the laser light can be 200 nm to 1500 nm. In the case of a pulsed laser, the pulse energy can be 0.5 mJ to 20 mJ. The speed at which the exposure region moves relative to the coated substrate can be 1 cm / s to 50 cm / s, preferably 5 cm / s to 30 cm / s.
By selecting the laser output, the length of the laser beam corresponding to the width of the exposure region, and the substrate transport speed, the equivalent circular diameter of the island-shaped seed cell can be adjusted. These are preferably 1 nm to 2 μm, preferably 1 nm to 200 nm, particularly preferably 1 nm to 100 nm. The average distance of the island-shaped seed zone can also be preset by these parameters. It is preferably in the range of 1 nm to 2 μm, preferably in the range of 1 nm to 500 nm, more preferably in the range of 1 nm to 100 nm. This distance may be any distance between the centers of adjacent island-shaped seed zones. However, it can also be the distance between two edges of adjacent island-shaped seed zones. The distance in that case is the lateral length of the gap between adjacent island-shaped seed zones. The formation of island-like seed zones is a self-organizing system, where the island-like seed zones are typically placed at the vertices of rectangular, in particular square or substantially square unit cells.

  The invention further relates to an apparatus for carrying out the above method, the apparatus comprising at least a laser generating a laser beam and an optical for expanding a laser beam having a dotted cross section into a laser beam having a linear cross section. Elements. The substrate is transported by the transport device to the expanded laser beam. The transport direction is transverse to the extending direction of the zone irradiated by the laser beam. The substrate can be unwound from one roll and wound on another roll. An apparatus for depositing a metal layer on the substrate can be placed between the two rolls. Behind this device in the transport direction is a device with a laser. Behind this device in the transport direction is a device capable of depositing carbon nanotubes on the seed zone. Additional equipment is also provided, such as equipment for performing additional processes performed to produce electrodes for lithium ion batteries from carbon nanotube coated films. The substrate can have a width of 100 mm to 1000 mm. Typically, the width is 300 mm to 600 mm. The substrate can be unwound from one roll and rewound onto another roll. However, the substrate can also be a hard wafer having a diameter in the range of 50 mm to 450 mm. In particular, silicon and sapphire are considered for the wafer as the material of the substrate. As the substrate that can be wound, a flexible metal substrate, for example, an aluminum or copper substrate is preferably used. It is preferable to use aluminum, nickel, silver, gold, lithium, titanium, vanadium, chromium, iron, platinum or tantalum for the metal layer. Typical layer thickness is between 1 nm and 200 nm.

FIG. 1 is a schematic perspective view of the exposure method. FIG. 2 is a detailed enlarged view of FIG. 1 regarding the arrangement of the island-like seed zones 3. FIG. 3 shows a longitudinal sectional view of the substrate of FIG. 1 at a position where the magnified laser beam 5 produces an exposure region 15. FIG. 4 schematically shows an apparatus for carrying out the method according to the invention.

Embodiments of the present invention will be described below with reference to the drawings.
The method according to the invention not only processes substrates prepared on rolls, in particular substrates coated with metal layer 2, but also processes uncoated substrates 1 and processes substrates that exist as semiconductor wafers. Suitable for the method. FIG. 1 schematically shows various ways in which a substrate 1 coated with a metal layer 2 is wound on a first roll 9 and then unwound in the transport direction T. The laser 6 generates a laser beam 4 having a dotted cross section. The point-like laser beam 4 is enlarged into a linear laser beam 5 by the optical enlargement device 7. The width of the linear laser beam 5 corresponds at least to the width W of the substrate 1 in the region on the layer 2 where it hits.

The expanded laser beam 5 produces a linear exposure area 15 on the surface of the substrate coated with the coating 2. By transporting the substrate in the transport direction T, the linear exposure region 15 moves on the layer 2 of the substrate 1 in the lateral direction with respect to the extending direction. Energy in the form of heat is combined at the same time with the metal layer 2 on each point of the exposure region 15 by energy impact by a pulsed or continuously generated laser beam. As a result, since the entire linear surface is exposed at the same time, a temperature gradient is not substantially formed in the extending direction of the straight line, and only the moving direction of the exposure region 15 is formed. Thereby, the material of the metal layer 2 is organized into the island-shaped seed zone 3. The island-shaped seed zone 3 is located on a substantially square apex and has a diameter R _Dot of 1 nm to 100 nm. Each island seed zones 3 are spaced apart by a distance _{D Dc} of 1nm~100nm each other.

  The conveyance speed is about 5 cm / s to 30 cm / s.

  FIG. 4 schematically shows the configuration of an apparatus for depositing the carbon nanotubes 16 on the substrate 1. For example, a substrate 1 made of a metal such as copper or aluminum is unwound from the first roll 1 and conveyed through a manufacturing apparatus composed of a plurality of stages at a predetermined conveying speed. The processed substrate is wound up around the second roll 10 again.

  The apparatus has a first station 11 on which a metal layer 2 is deposited on a substrate 1. Thereafter, in the second station 12, the surface treatment of the metal layer 2 is performed using an enlarged laser beam by the apparatus configured as shown in FIG. 1, and the dotted seed zones 3 separated from each other are formed. The Thereafter, carbon nanotubes 16 are deposited on the seed zone 3 at a further station 13. Thereafter, one or more further stations 15 can carry out further processing steps which are usually necessary for producing electrodes for lithium ion batteries.

  In the figure, in order to show a uniform arrangement of the island-like seed zones 3 on the substrate 1, the island-like seed zones 3 are shown greatly enlarged. In practice, these islands 3 are separated by submicron regions. The region of the island-like seed zone 3 and the distance between the island-like seed zones 3 can be adjusted reproducibly by the above-described parameters such as the laser output and the layer thickness.

  In the method of the invention, a closed metal layer is first deposited on an unstructured substrate. Preferably, the metal layer completely covers the substrate surface so that the width of the metal layer matches the width of the substrate. The expanded laser beam corresponds to the width of the metal layer with respect to its width and is used to simultaneously energize the metal layer over its entire width. When the substrate is transported to the linear laser processing region in a direction transverse to the direction of the laser beam expanded linearly, the laser processing region moves on the substrate.

  Although not structured on or under the metal layer, a plurality of metal islands are formed in the region of the laser processing zone that are substantially equally spaced. The metal layer recedes locally on the island-like region. The island seed zone formed thereby is typically located at the apex of a rectangular unit cell.

  Accordingly, the present invention relates to a method for generating a structured seed layer for depositing carbon nanotubes 16 on the structured seed layer. In that case, on the unstructured surface of the substrate 1, a closed uniform metal layer 2 is first coated and subsequently the metal layer 2 is energized by a laser beam 4. In that case, the laser beam 4 is expanded into a linear beam 5 in cross section, thereby exposing the linear exposure region 15 of the metal layer 2 simultaneously. In that case, the exposure region 15 moves at a predetermined moving speed in a direction transverse to its extending direction on the metal layer 2, and the laser beam 4 in the exposure region 15 imparts energy to the metal layer at a predetermined energy density. By doing so, the metal layer 2 is transformed into a single substantially uniform sized island 3, which are substantially equidistant from one another. The equivalent circular diameter of the island 3 is smaller than 2 μm, and the distance between the two adjacent islands 3 without the metal layer is smaller than 2 μm.

  The entire extending portion corresponding to the length of the laser beam 5 in the moving direction and corresponding to the width of the exposure region 15 is preferably in the range of 0.5 mm to 1.5 mm. With a pulsed laser beam, the pulse sequence is so fast that the exposure area 15 is exposed quasi-continuously. In particular, the pulse frequency is substantially larger (10 times) than the quotient of the moving speed and the width of the exposure area. There is no temperature gradient in the metal layer 2 melted by the laser treatment over the length of the exposure region 15 which is also the linear direction of the expanded laser beam, but a large temperature gradient is formed in the moving direction of the laser beam.

  The above description serves to explain the invention as a whole and further develops the current technology independently, at least by a combination of the following features.

  The laser beam 4 is expanded into a linear beam 5 in cross-section, which is used to simultaneously expose a linear exposure region 15 of the metal layer 2, which exposure region 15 extends in its extending direction on the metal layer 2. A method characterized by moving in a horizontal direction with respect to.

  A method in which the width W of the laser beam corresponds to the width of the substrate 1 and is in the range of 20 mm to 1000 mm, or 100 mm to 1000 mm.

  A method in which the width W of the expanded laser beam 5 is 300 mm to 600 mm.

  A method wherein the substrate 1 is made of silicon, sapphire, aluminum, copper, or other metal.

  A method in which the metal layer 2 is made of aluminum, nickel, silver, gold, lithium, titanium, vanadium, chromium, iron, platinum, tantalum or other noble or non-noble metals.

  A method wherein the thickness of the metal layer is in the range of 1 nm to 200 nm.

  A method, characterized in that the length of the laser beam extending in the transverse direction with respect to the width W of the expanded laser beam 5 corresponding to the width of the exposure region 15 is between 0.5 mm and 5 mm.

  A method wherein the wavelength of light generated by the laser 6 is in the range of 200 nm to 1.5 μm.

  A method wherein the laser 6 emits pulsed or continuous light and the pulse energy is in the range of 0.5 mJ to 20 mJ.

  A method characterized in that the speed at which the expanded laser beam 5 moves on the metal layer 2 is between 1 cm / s and 50 cm / s, preferably between 5 cm / s and 30 cm / s.

  The island-shaped seed zone 3 has an equivalent circular diameter of 1 nm to 2 μm, preferably 1 nm to 500 nm, particularly preferably 1 nm to 100 nm, and / or the distance between the centers of the adjacent island seed zones 3 is 1 nm. A method characterized in that it is in the range of ˜2 μm, preferably 1 nm to 500 nm, more preferably 1 nm to 100 nm.

  A method characterized by a rectangular, particularly square or substantially square arrangement of island-like seed zones 3.

  The laser beam 4 is expanded to produce means 9, 10 for conveying a substrate 1 on which a metal layer 2 is coated, a laser 6 for generating a laser beam 4 and a linear exposure area 15. And the means 7 is arranged so that the linear exposure area 15 extends perpendicularly to the transport direction of the substrate 1.

  An apparatus for unwinding the substrate wound on the roll 9 and means 11 for coating the substrate 1 with the metal layer 2 arranged before the means 7 for expanding the laser beam in the conveying direction of the substrate 1 And means 13 for depositing the carbon nanotubes 16 on the island-like seed zones 3 and means for supporting the roll 10 on which the treated substrate is wound up.

  All the disclosed features are essential to the invention (although individually but in combination with each other). The disclosure of related / attached priority documents (copies of previous applications) is also fully incorporated into the present disclosure for the purpose of including the characteristics of these documents in the claims of the present application. The dependent claims are characterized by independent developments from the prior art using these features, in particular for filing a divisional application on the basis of these claims.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Metal layer 3 Island 4 Laser beam 5 Expanded laser beam 6 Laser 7 Optical system 8 Unit cell 9, 10 reel 11 First station 12 Second station 13 Further station 14
15 Exposure area 16 Carbon nanotube T Transport direction W Width

Claims (14)

A method of forming a structured seed layer for depositing carbon nanotubes (16) on a structured seed layer, wherein a metal layer (2) pre-coated on a substrate (1) comprises a laser beam (4) In the method, wherein the metal layer (2) is transformed into an isolated island (3) by being energized by
The laser beam (4) is expanded into a beam (5) that is linear in cross section, whereby a linear exposure region (15) of the metal layer (2) is simultaneously exposed, the exposure region (15) being And moving laterally with respect to the extending direction on the metal layer (2).   The method according to claim 1, characterized in that the width (W) of the laser beam corresponds to the width of the substrate (1) and is in the range of 20 mm to 1000 mm, or 100 mm to 1000 mm.   Method according to claim 2, characterized in that the width (W) of the expanded laser beam (5) is in the range of 300 mm to 600 mm.   4. The method according to claim 1, wherein the substrate (1) consists of silicon, sapphire, aluminum, copper or another metal.   The metal layer (2) is made of aluminum, nickel, silver, gold, lithium, titanium, vanadium, chromium, iron, platinum, tantalum, or another noble or non-noble metal. The method according to any one.   The method according to claim 1, wherein the thickness of the metal layer is in the range of 1 nm to 200 nm.   The length of the laser beam extending in the transverse direction with respect to the width (W) of the expanded laser beam (5) corresponds to the width of the exposure region (15) and is 0.5 mm to 5 mm. A method according to any one of claims 1-6.   The method according to claim 1, wherein the wavelength of the light generated from the laser is in the range of 200 nm to 1.5 μm.   9. The method according to claim 1, wherein the laser (6) generates pulsed light or continuous light, and the pulse energy is in the range of 0.5-20 mJ.   The speed at which the expanded laser beam (5) moves on the metal layer (2) is in the range of 1 cm / s to 50 cm / s, preferably in the range of 5 cm / s to 30 cm / s. 10. A method according to any of claims 1 to 9, characterized in that   The island-like seed zone (3) has an equivalent circular diameter of 1 nm to 2 μm, preferably 1 nm to 500 nm, particularly preferably 1 nm to 100 nm, and / or between the centers of adjacent island (3) -like seed zones The method according to claim 1, wherein the distance is in the range of 1 nm to 2 μm, preferably 1 nm to 500 nm, particularly preferably 1 nm to 100 nm.   12. A method according to any of the preceding claims, characterized in that the island-shaped seed zone (3) has a rectangular, in particular square or substantially square arrangement.   Device for carrying out the method according to any of claims 1 to 12, comprising means (9, 10) for transporting a substrate (1) on which a metal layer (2) is coated, A laser (6) for generating a laser beam (4) and means (7) for expanding the laser beam (4) to produce a linear exposure area (15); The apparatus (7) is characterized in that the linear exposure region (15) is arranged so as to extend perpendicular to the transport direction of the substrate (1).   An apparatus for unwinding a substrate wound on a roll (9) and the substrate (1) arranged before the means (7) for expanding the laser beam in the transport direction of the substrate (1) Means (11) for coating the substrate with a metal layer (2), means (13) for depositing carbon nanotubes (16) on the island-like seed zone (3), and the treated substrate is wound up 14. Device according to claim 13, characterized in that it comprises means for supporting the roll (10) to be used.

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